You may be wondering why you would want type hinting in a dynamic language. This can come in very handy especially if you are looking to enforce a specific type or need to ensure that you are indeed working with say an integer. Since this is written in C, it will be far faster than actually type casting it yourself or enforcing it yourself. General speed improvements are always nice to have.
He includes two code examples of it in use and points to the php.internals mailing list for the vote count either way. So far (as of the time of those post) the results seem mixed with some recommending it outright while others suggest waiting until the spec is completely done before integration (PHP6?).